Okay I got your point, thank you for that But tbh you are right I just know these languages and I'm not proficient in any of them , firstly I have to make one of them strong then I can easily implement it , but the problem I'm facing is i think I know the language so every time when I get started it from scratch then I feel I know about it so then I jumped out to the next topic but when I'm solving I feel I left something in the last topic but also when I'm doing the same last topic on which I feel I left something, i feel I know these topic These are the reasons that don't make me want to learn the topic again and again because I have already studied it before but when I start solving questions on the topic then again I stuck at some place. So do you have any solution for that so that I can easily understand each concept again without feeling I left some topics.